Abstract

BACKGROUND:

International collaborative research is a mechanism for improving the development of disease-specific therapies and for improving health at the population level. However, limited data are available to assess the trends in research output related to orphan diseases.

METHODS AND FINDINGS:

We used bibliometric mapping and clustering methods to illustrate the level of fragmentation in myeloma research and the development of collaborative efforts. Publication data from Thomson Reuters Web of Science were retrieved for 2005-2009 and followed until 2013. We created a database of multiple myeloma publications, and we analysed impact and co-authorship density to identify scientific collaborations, developments, and international key players over time. The global annual publication volume for studies on multiple myeloma increased from 1,144 in 2005 to 1,628 in 2009, which represents a 43% increase. This increase is high compared to the 24% and 14% increases observed for lymphoma and leukaemia. The major proportion (>90% of publications) was from the US and EU over the study period. The output and impact in terms of citations, identified several successful groups with a large number of intra-cluster collaborations in the US and EU. The US-based myeloma clusters clearly stand out as the most productive and highly cited, and the European Myeloma Network members exhibited a doubling of collaborative publications from 2005 to 2009, still increasing up to 2013.

CONCLUSION AND PERSPECTIVE:

Multiple myeloma research output has increased substantially in the past decade. The fragmented European myeloma research activities based on national or regional groups are progressing, but they require a broad range of targeted research investments to improve multiple myeloma health care.

Multiple myeloma mapping and clustering of authors with >20 publications.

These network maps illustrate the collaboration networks of all authors in the datasets. Each vertex in the map illustrates an author, the size of the vertex indicates the number of papers published by this author, on the respective subjects in the given time period. The thickness of lines between authors indicates the degree of collaboration between them and the colours indicate which authors are associated with the same cluster. EU members form the clusters my1, my6, my5, and my7. My1 is the yellow cluster spread over the majority of the map, while my6 is shown as a white cluster towards the bottom. My5 and my7 are two-person clusters. The majority of EMN members are present in my1, with the exception of H Goldschmidt from GMMG, Germany, in cluster my6. The three most highly cited clusters from the US, my2, my3, and my4 include the red cluster, which includes KC Anderson from Dana-Farber Cancer Institute (DFCI), Boston, MA, the blue cluster, which includes B Barlogie from the University of Arkansas Medical Sciences (UAMS), Little Rock, AR, and the green cluster, which includes A Dispenzieri and SV Rajkumar from the Mayo Clinic in Rochester, MN, Phoenix, AZ, and Jacksonville, FL.

This network diagram illustrates the change in collaborative research over the periods shown; only authors with more than 20 papers in each period are included. Green circles represent EMN members, while the other colours represent the three major US clusters (my2: yellow, my3: red, my4: blue). The green edges represent inter-EMN collaboration while blue edges represent collaboration between EMN and non-EMN authors.

A: The two cluster density measures are shown for three year intervals (each data point is calculated from the displayed year and two years ahead to allow networks to form). The collaboration fraction is calculated as the number of papers with more than one author from the EMN, divided by all papers with at least one author from the EMN. B: the cluster density measures for the entire period are compared to 1,000 randomly drawn groups of the same size as the EMN group. C: The µs scores per year for the EMN group, when considering all publications (blue) versus those with only one EMN member (red) and at least two EMN members as authors (green). The shaded areas indicate the.95 confidence intervals. D: Similar to C, but using the PPtop10 indicator.